Considerable research effort has been devoted to improving the wear properties of tools and the like through material development. Most promising are those efforts involving material composites for tool hard facings or inserts, and which composites embody bonding of a plurality of highly abrasive-resistant particles in a carrying matrix. Illustrative of these composite materials are U.S. Pat. No. 3,800,891, issued to A. D. White, et al on Apr. 2, 1974; British Pat. No. 1,338,140 published Nov. 21, 1973; U.S. Pat. No. 3,970,445 issued July 20, 1976 to P. L. Gale, et al; and U.S. Pat. No. 4,011,051 issued Mar. 8, 1977 to E. L. Helton et al. It is noted that both of the aforementioned patent applications are assigned to the assignee of the present invention.
In general, prior composite materials such as those mentioned above have been relatively expensive due to the cost of the individual elements thereof, or due to the complexity of the manufacturing process associated therewith. Naturally, such costs must be measured against the extended wear life gained by utilizing the new composite material in place of the old.
When these composite materials are used for ground-engaging tools, for example, the need for certain physical qualities in the material become readily apparent. In such a working environment, many of the known wear-resistant alloys are found to be unsuitable since they are so hard that they are brittle and, therefore, are not resistant to the frequent shocks encountered. Particularly, the abrasive-resistant particle carrying matrix must be tough and shock resistant, and yet be hard enough to exhibit a relatively low rate of wear.
Furthermore, it is highly desirable that articles of the wear-resistant composite material be capable of being joined to a substrate by brazing or welding. Heretofore, this has presented a problem in that the physical qualities of the composite material have been impaired by the heat utilized during this joining stage, or in the subsequent heat treating operation of the substrate itself.